METHODS IN IMAGE PROCESSING TO IMPROVE UNDERSTANDING OF LASER INDUCED FLUORESCENCE RESPONSE IN MOSS TO METAL AND ENVIRONMENTAL STRESS
Date
2023
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Abstract
The ability to detect, measure, and locate the source of contaminants or radionuclides is of ongoing interest. There are many techniques for modeling atmospheric transport, sampling near sites of known contamination, and monitoring locations of interest. A widely-used tool for identification and bioremediation comes in the form of vegetation that can serve as indicators of recent and historic events. Large scale vegetation sampling, however, can be costly and labor-intensive, making a non-invasive in-situ technique an attractive alternative. Laser induced fluorescence (LIF) emission is quickly gaining efficacy as a tool to excite biologically-critical molecules, such as chlorophyll, and thereby observe the health of plants and algae. Such techniques are comparable to spectrophotometry, but with the potential benefit of being portable. The technique presented here uses images collected of LIF in moss (Thuidium plicatile) using a CMOS camera to identify the presence of different metals in healthy and impaired tissues. RGB data from each image is recorded and used to create density histograms of each color channel’s relative abundance of pixels where a specific color corresponds to a decimal code value ranging from 0 to 255. Changes in these histograms correlate to shifts in chlorophyll emission and help in the positive identification of very small tissue concentrations at nmol per cm2 levels of copper, zinc, and lead (Cu, Zn, Pb), as well as mixtures of metals. The research focuses on applications of the technique to compare metal contamination to background levels in moss tissues as well as to photoperiod and environmental stressors. Testing included a chlorophyll specific laser system (Semi-conductor diode 445 nm and 462 nm) alongside a Yg:ND pulsed system (355 nm and 532 nm).
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Environmental geology, Environmental science, Bryophyte, Environmental Contamination, Image Processing, Laser Induced Fluorescence, Metal Contamination, Metal Detection
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183 pages
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